I wouldn't count non-voluntary prison labour as selling labour anyway, since...ya know, indentured servitude and all.
Any definition or categories of class are going to have exceptions so debating over them exclusively is pointless either way. And class warfare between the people "desparately trying to keep their home" and "desparately trying to get a home" isn't that useful
There's always the
proposed expanded class system from UK sociologists:
Precariat - This is the poorest and most deprived class group. People in this group score low for economic, social and cultural factors. They tend to mix socially with people like them. Jobs in this group include cleaner, van driver and care worker. They tend not to have a broad range of cultural interests. People in this group often live in old industrial areas away from urban centres. More than 80% rent their home.
Emergent service workers - This class group is financially insecure with low scores for savings and house value, but high for social and cultural factors. This is the youngest of all the class groups. People in this group have the highest score for emerging culture, which includes going to gigs, using social media and playing sport. They are an urban group, living in inexpensive locations in large cities. They socialise with a broad range of people. Jobs in this group include chefs, nursing auxiliaries and production assistants.
Traditional working class - This class group scores low for economic, social and cultural factors, but they do have some financial security. Many people in this group own their own home. They tend to mix socially with people like themselves. They tend not to enjoy emerging culture, such as going to the gym or using social media. This group has the oldest average age. Jobs in this group include lorry drivers, cleaners and electricians.
New affluent workers - This class group is sociable, has lots of cultural interests and sits in the middle of all the groups in terms of wealth: This youthful class group is economically secure, without being well off. These people have high scores for emerging culture, such as watching sport, going to gigs and using social media. They do not tend to participate in highbrow culture, such as classical music and theatre. People in this group are likely to come from a working class background. Many people in this group live in old manufacturing centres.
Technical middle class - This is a small, distinctive and prosperous new class group. People in this group tend to mix socially with people similar to themselves. They prefer emerging culture, such as using social media, to highbrow culture such as listening to classical music. Many people in this group work in research, science and technical occupations. They tend to live in suburban locations, often in the south east of England. They come from largely middle class backgrounds.
Established middle class - This is the most gregarious and the second wealthiest of all the class groups. People in this group enjoy a diverse range of cultural activities. They socialise with a broad range of people. Many work in management or the traditional professions. Most come from middle class backgrounds. They often live outside urban areas
Elite - This is the wealthiest and most privileged group. They are the biggest earners. They score highest for social, cultural and economic factors. Many went to private school and elite universities - 24% of people in this group were privately educated, far more than in any other class group. This group is exclusive and very hard to join, most come from very privileged backgrounds. 97% of people in this group own their own home.